commit 20a5239a upstream.

Christoph's patch e244a0ae doesn't display
the discard option in /proc/mounts, leading to some confusion for me.
Here's the missing bit.
Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
Acked-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>